The relationship between cocaine use during pregnancy and infant outcome has become an area of interest in recent years and constitutes a major health concern. However, prospective study designs are rare and adequate sample sizes difficult to achieve. This prospective study will assess cocaine use during each trimester of pregnancy and infant outcome at birth and at 8 months. Unique features of this proposal include measures of the infant's physical, neurophysiological, behavioral and developmental characteristics. This study will: (1) Assess cocaine and other substance use habits of women at the end of the first second and third trimesters and at 8 months postpartum. (2) Examine the infants at delivery and 8 months of age with respect to physical, neurophysiological, behavioral and developmental characteristics. (3) Measure maternal attitudes toward the pregnancy, medical history, pregnancy, labor and delivery conditions and mother- infant interaction at delivery. (4) Determine the spectrum of regional electroencephalographic patterns and sleep organization in children in the neonatal period and at follow-up. In the proposed study, the effect of cocaine will be analyzed by trimester of pregnancy. Careful assessment of sociodemographic characteristics, psychiatric symptom levels and other drug use will allow the measurement of the relationship between cocaine use and infant outcome while controlling for these confounding factors. This will allow the separation of the direct teratogenic effect of cocaine use from the contributing effect of other factors that accompany cocaine use.